graphics/djview4: port improvements

There are some improvements for graphics/djview4 port to make it usable on
desktop. For example, while there is a need to use register-djview-menu shell
script (on post-install stage, which is not available currently) to setup the
djview4 menu entries and icons, it is possible to install them manually, as
described in ${WRKSRC}/desktopfiles/README file. Also this application is
translated to different languages.

• add LICENSE_FILE
• add libtiff.so to LIB_DEPENDS as required shared library
• add desktop-file-utils to USES and sort it
• add linguist to USE_QT4, because there are available messages to translate
• add --disable-desktopfiles option to CONFIGURE_ARGS, which do not install scripts to register icons and menus
• replace CFLAGS and CXXFLAGS with CPPFLAGS for include directory
• improve sed patch by using & for replacement part
• strip web-plugin library, install icons and desktop files on post-install stage
• remove unneeded files after --disable-desktopfiles option from pkg-plist
• add translated files, icons and desktop files to pkg-plist

PR: 196409
Submitted by: lightside <lightside@gmx.com>